The present disclosure relates to a power transfer device that includes a transmission, a drive pinion gear to which power from the transmission is transferred, a differential ring gear disposed below the drive pinion gear and meshed with the drive pinion gear, a differential gear coupled to the differential ring gear, and a cover member that covers at least a part of the differential gear.
There has hitherto been known a power transfer device that includes a reduction gear (drive pinion gear) to which power from an automatic transmission is transferred, a final gear (differential ring gear) meshed with the reduction gear and meshed with a differential case, and a final gear cover that covers a part of the final gear, in which oil raked up along with rotation of the final gear is led to a meshing portion between the reduction gear and the final gear along the inner surface of the final gear cover to lubricate and cool the reduction gear (see Japanese Patent Application Publication No. 2012-220004, for example). In the power transfer device, a window portion is provided at the middle of the final gear cover, and part of the oil raked up along with rotation of the final gear is discharged to the outside of the final gear cover via the window portion. In addition, a reduction gear cover (shield structure) shaped along the outer periphery of the reduction gear is provided in the vicinity of the reduction gear. Consequently, it is possible to block oil splashed in the direction against the rotational direction of the reduction gear from the window portion using the reduction gear cover, and to suppress an increase in resistance against rotation of the reduction gear.
In addition, there is also known a power transfer device that includes a case member that houses a speed change mechanism and a differential device (differential gear) and a reservoir plate (cover member) that surrounds at least a part of the differential device so as to define a differential chamber in which the differential device is disposed (see International Patent Application Publication No. 2011/121861, for example). In the power transfer device, the reservoir plate is disposed so as to cover the differential device from the side opposite to the case member and tightly contact the inner peripheral surface of a rib member that extends from the case member along the outer peripheral surface of a ring gear (differential ring gear) of the differential device. Consequently, in the power transfer device, an inflow of oil into a space around the ring gear (differential ring gear) of the differential device is prevented to suppress an increase in resistance against rotation of the ring gear.